Abilities

Sivir's only damage on demand ability, great for farming and will deal high damage later on. Keep in mind that it does less damage for each target you hit, so when aiming for champions try not to hit any minions.

This ability cannot be dodged.
This ability cannot crit.
This ability does not apply on hit passives.

The damage is based on your total attack damage and will do less damage to each target afterwards. Many people think this ability is bad, however with enough attack damage and attack speed you can farm minions like a boss and you will do tons of damage in a team fight that nobody is really expecting to see.

Not the best ultimate in the game, but since Sivir is a support it fits pretty well. This can really help you a lot in team fights and tower pushing, it's also a nice escape ability.

Introduction

Sivir is a champion that you do not see often on the fields of battle. Many people dismiss her as a bad champion and will not be happy to see her on their team. This guide is obviously intended to show them otherwise :).

While she is not a pure AD or a pure Support, the balance of the two has it's rightful place in any team and Sivir is almost always a good addition. She is great at clearing out minions and with Teleport she can easily backdoor a turret/inhibitor or 2 and then get out before being caught (we hope).

Summoner Abilities

Teleport is pretty much a must for Sivir, because it allows her to sneak around and quickly clear a turret/inhibitor while the enemy is occupied elsewhere.

We will also need some sort of escape spell as we cannot rely on the ultimate to be up.
Personally I go with Flash, as it allows you to skip terrain and immediately puts you out of range.

Ghost can be used however if an enemy is on your tail it will likely not save you in time.

Exhaust is also a possible option, but it is mostly good for team fights where you can disable one of their players to get the upper hand.

Because Sivir is a squishy champ with a small range, few on demand damage abilities and she does not benefit greatly from magic damage or critical strike, I feel like the offensive masteries are a waste, however if you really prefer them by all means do it.

Any spells that are not mentioned on the list are most likely blocked.

Ricochet Mechanics:

Bounces cannot be dodged.
Bounces are reduced by armor.
Bounce damage is based only on your attack damage.
Bounces do not proc on hit affects.

Trinity Force/Lich Bane/Sheen do not add extra damage to the bounces.
A crit from your main damage does not increase bounce damage.

Items

This is where things get a bit tricky because there are many different builds for Sivir floating around and it will depend on the enemy as well. However I am presenting my own personal choices which I think cannot be argued with if you want to get the best out of this champion.

Next you will want to finish up Manamune. I can already hear people going OMGWTF MANAMUNE?!!! Yes. This item allows you to turn on your and basically never turn it off while spamming as well. It also adds 20 attack damage as well as 2% of your max mana as attack damage, this adds up to 87 attack damage from Manamune alone at level 18.

The last core item is [item=Stark's Fervor]. This basically adds an awesome aura for your team, and even if you happen to be with 4 AP champions (ask yourself how that happened) it's still a nice item for you alone.

After that you can consider a few different items depending on your preference and the enemy team build. One item I always add is The Bloodthirster because it adds a lot of damage and the lifesteal along with Stark's Fervor allows you to stand your ground in a 1v1.

More viable choices are listed below.

Best choices:

Sword of the Divine: This item is really nice because it adds even more speed combined with a strong passive and a decent active. Banshee's Veil: You already have Spell Shield but this item adds another shield along with health, mana and magic resistance which helps you stay alive. The extra mana also affects your Manamune. Hexdrinker: This item is pretty nice for people who have gank ulti's like Karthus or Ashe it can save your life and adds decent damage. Last Whisper: This item should only be used if the enemy is stacking lots and lots of armor (around 100+) Then the passive combined with the attack damage is a great upgrade.

Decent choices:

Frozen Mallet: Even though the slow only works on your main target the extra health keeps you alive while also adding some slight damage. The slow from this item could help you get a gank when chasing people down or fighting 1v1. The Black Cleaver: Another good item but because it does not affect Sivir's bounces the passive becomes a little bit of a waste. It is still very good against your main target and has great stats.
[item=Madred's Bloodrazor]: This is an item that should really only be used if the enemy team has many high health champions because once again the passive does not affect your bounces. Sword of the Occult: Only viable if you are getting lots of kills and basically facerolling the enemy team.

If heavily focused:

Quicksilver Sash: A rarely used item that could possibly save you from death, use against heavy CC. Frozen Heart: Very useful against a highly AD based team, also grants extra damage through Manamune. Thornmail: Almost the same as the item above but not granting as many benefits in my opinion. Guardian Angel: If you really keep dieing first and getting all the focus on you this item will help make the enemy focus someone else or waste all their spells on you only to find out you are not dead yet.

Not Reccomended:

Youmuu's Ghostblade: While almost every single stat on this item is useful as well as the active, crit is really not good for Sivir because it only affects her main target. Wit's End: Another item that would be decent if the passive worked on bounce. Infinity Edge: Because you do not stack any crit this item goes to waste and Manamune actually gives more damage in the end. Phantom Dancer: Awesome item, but the crit makes it a total waste.

Pros / Cons

Pros:

Great solo farmer/pusher
Helps the team push faster.
Can provide many team battle aura's.
Has a nice harassing tool.
Can absorb enemy spells.